Composition for electrochemical device functional layer, functional layer for electrochemical device, laminate for electrochemical device, and electrochemical device

Abstract

A composition for an electrochemical device functional layer contains a binder, heat-resistant fine particles, and a particulate polymer that has a volume-average particle diameter of more than 1.0 μm and not more than 10.0 μm and that includes a polymer A including a (meth)acrylic acid ester monomer unit and an acidic group-containing monomer unit and a polymer B that is a different polymer from the polymer A.

1 . A composition for an electrochemical device functional layer comprising a particulate polymer, a binder, and heat-resistant fine particles, wherein
 the particulate polymer includes a polymer A and a polymer B,   the polymer A is a polymer including a (meth)acrylic acid ester monomer unit and an acidic group-containing monomer unit,   the polymer B is a polymer having a different chemical composition from the polymer A, and   the particulate polymer has a volume-average particle diameter of more than 1.0 μm and not more than 10.0 μm.   
     
     
         2 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the acidic group-containing monomer unit of the polymer A is a (meth)acrylic acid monomer unit. 
     
     
         3 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the polymer A has a glass-transition temperature of not lower than 60° C. and not higher than 85° C. 
     
     
         4 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the polymer A has an acid value of not less than 0.5 mg KOH/g and not more than 7 mg KOH/g. 
     
     
         5 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the polymer A has a weight-average molecular weight of not less than 5,000 and not more than 100,000. 
     
     
         6 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the particulate polymer includes the polymer A in a proportion of not less than 0.1 mass % and not more than 10 mass % based on the particulate polymer. 
     
     
         7 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the polymer B includes an aromatic vinyl monomer unit. 
     
     
         8 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the heat-resistant fine particles are inorganic fine particles, and the inorganic fine particles have a volume-average particle diameter that is not less than 2% and not more than 25% of the volume-average particle diameter of the particulate polymer. 
     
     
         9 . The composition for an electrochemical device functional layer according to  claim 1 , wherein the binder is a polymer including a (meth)acrylic acid ester monomer unit and having a different chemical composition from the polymer A and the polymer B. 
     
     
         10 . A functional layer for an electrochemical device formed using the composition for an electrochemical device functional layer according to  claim 1 . 
     
     
         11 . The functional layer for an electrochemical device according to  claim 10 , wherein
 the functional layer for an electrochemical device has a structure in which the particulate polymer is partially embedded in a heat-resistant fine particle layer that contains the heat-resistant fine particles, and   a ratio of the volume-average particle diameter of the particulate polymer relative to thickness of the heat-resistant fine particle layer is not less than 1.0 and not more than 5.0.   
     
     
         12 . The composition for an electrochemical device functional layer according to  claim 8 , further comprising, as the heat-resistant fine particles, organic fine particles that have a volume-average particle diameter that is not less than 50% and not more than 150% of the volume-average particle diameter of the particulate polymer and that have a glass-transition temperature or melting point of 150° C. or higher or do not have a glass-transition temperature or melting point within a range of 200° C. or lower. 
     
     
         13 . The composition for an electrochemical device functional layer according to  claim 12 , wherein an amount of the organic fine particles is not less than 20 parts by mass and not more than 1,000 parts by mass relative to the particulate polymer. 
     
     
         14 . A functional layer for an electrochemical device formed using the composition for an electrochemical device functional layer according to  claim 12 . 
     
     
         15 . The functional layer for an electrochemical device according to  claim 14 , wherein
 the functional layer for an electrochemical device has a structure in which the particulate polymer and the organic fine particles serving as the heat-resistant fine particles are partially embedded in a heat-resistant fine particle layer that contains the heat-resistant fine particles, and   a ratio of the volume-average particle diameter of the particulate polymer relative to thickness of the heat-resistant fine particle layer is not less than 1.0 and not more than 5.0.   
     
     
         16 . A laminate for an electrochemical device comprising: a substrate; and a functional layer for an electrochemical device formed on the substrate, wherein the functional layer for an electrochemical device is the functional layer for an electrochemical device according to  claim 10 . 
     
     
         17 . An electrochemical device comprising the laminate for an electrochemical device according to  claim 16 .